Generally, a refrigerator has a plurality of storage chambers for accommodating stored things to keep food frozen or refrigerated, and one surface of each of the storage chambers is formed to be opened for the food to be received or taken out. The plurality of storage chambers include a freezing chamber for keeping the food frozen and a refrigerating chamber for keeping the food refrigerated.
In the refrigerator, a refrigeration system in which a refrigerant is circulated is driven. The refrigeration system includes a compressor, a condenser, an expander and an evaporator. The evaporator may include a first evaporator which is provided at one side of the refrigerating chamber, and a second evaporator which is provided at one side of the freezing chamber.
Recently, a refrigerator in which the evaporator and the expander are installed at the refrigerating chamber and the freezing chamber, respectively has been developed. In this refrigerator, an amount of the refrigerant supplied from the compressor to each evaporator is adjusted by controlling each expander, and each internal temperature of the refrigerating chamber and the freezing chamber are maintained at a cold temperature and a freezing temperature.
Also, in consideration of target temperatures of the freezing chamber and the refrigerating chamber that are considerably different from each other, a refrigerator in which a compressor for freezing and a compressor for refrigeration having different refrigeration capacities from each other are installed has been developed. In this refrigerator, each compressor is controlled based on the target temperatures of the refrigerating chamber and the freezing chamber, and thus each internal temperature of the refrigerating chamber and the freezing chamber are maintained at the target temperatures.
Here, the refrigeration capacity of the compressor for refrigeration is reduced to about 60% of that of a conventional compressor to increase an evaporation temperature of the refrigeration cycle for cooling the refrigerating chamber.
That is, the refrigeration further includes a small compressor having a small refrigeration capacity to increase the evaporation temperature of the refrigeration cycle for cooling the refrigerating chamber.
However, in a conventional refrigeration system, a subsidiary condenser may be provided so that a plurality of condensing processes are performed in the refrigeration cycle in some cases, but, in this case, there is a problem in that a radiant value of a main condenser is lowered due to the subsidiary condenser, and thus cooling efficiency is reduced.